The present invention is directed to a welding apparatus, and more particularly to a percussive arc welding apparatus. In the electrical/electronic product assembly, the use of percussive arc welding to join, for example, electrical conductors, is common. Percussive arc welding is accomplished by initiating an electric arc between the two components being joined, and then forging the components together after the arc has melted the adjacent surfaces of the components. Typical applications include welding electrical wires, in the size range of No. 20 AWG to No. 26 AWG, to electrical housing and connector contacts.
A critical component of the percussive arc welding system is the actuator that provides a precise and consistent forging action. The actuator must also conduct the electrical welding current while isolating the high voltage arc initiating pulse from other external circuits and fixtures. The actuator drive mechanism must have low mass, relative to the components being welded, in order to minimize the xe2x80x9creboundxe2x80x9d after the forging impact.
Various devices are currently available for use in percussive arc welding of the components of interest. These devices, however, suffer from the disadvantage that the actuator has a high mass relative to the component being welded. This results in undesirable xe2x80x9creboundxe2x80x9d after the forging impact, which not only adversely effects the forging action, but also may even damage the components being forged.
Therefore, there is a need in the industry for a percussive arc welding apparatus in which the detrimental effects of rebound are significantly reduced or eliminated.
The principal object of the present invention is to provide a percussive arc welding apparatus that overcomes the rebound drawbacks associated with conventional percussive arc welding devices.
Yet another object of the present invention is to provide a percussive arc welding apparatus which significantly reduces or eliminates adverse effects of actuator rebound on the components being forged.
Still yet another object of the present invention is to provide a percussive arc welding apparatus which provides precise and consistent forging of the components.
An additional object of the present invention is to provide a percussive arc welding apparatus in which the effects of the actuator rebound are further mitigated by a resilient member positioned between the solenoid and the movable actuator rod holding block.
Yet an additional object of the present invention is to provide a percussive arc welding apparatus in which a resilient member located between the solenoid and the movable actuator rod holding block, partially absorbs the shock upon impact.
Still yet an additional object of the present invention is to provide a percussive arc welding apparatus which provides excellent high voltage isolation between the actuator shaft and the solenoid.
A further object of the present invention is to provide a percussive arc welding apparatus in which the actuator shaft mass is significantly reduced by providing a non-rigid connection between the actuator shaft and the solenoid to significantly reduce or eliminate the adverse effects of the actuator rod rebound during the forging action.
Yet a further object of the present invention is to provide a percussive arc welding apparatus which is simple in design, significantly less complex than the conventional devices, and uses inexpensive commercially available hardware.
In summary, the main object of the present invention is to provide a percussive arc welding apparatus which significantly reduces or eliminates the adverse effects of the actuator rebound during the forging action, provides excellent high voltage isolation, is simple in design and relatively inexpensive to manufacture.
In accordance with the present invention, a percussive arc welding apparatus includes a generally cylindrical actuator body having front and rear end portions and defining an internal recess. The front end of the body includes an opening. A solenoid assembly is provided in the rear end portion in the internal recess of the body, and an actuator shaft assembly is provided in the front end portion in the internal recess of the actuator body. The actuator shaft assembly includes a generally cylindrical actuator block having first and second end portions, and an actuator shaft having a front end extending through the opening in the actuator body, and the rear end connected to the first end portion of the actuator block. The second end portion of the actuator block is in operational engagement with the solenoid shaft by a non-rigid connection to reduce the adverse rebound effects of the actuator shaft. A generally transversely extending pin is rigidly secured to the rear end of the shaft. One end of the pin is received in a slot in the nose housing sleeve to prevent rotation of the actuator shaft during operation of the apparatus.